Branding pharmaceutical dosage forms, food and confectionery products with aqueous ingestible inks

ABSTRACT

A method of marking forms such as pharmaceutical tablets, capsules, confectionery and food with a water based ingestible ink comprising mixing pigments, a polymer, and optionally a plasticizer into water to form an ink dispersion, and printing the ink dispersion onto said forms to form a trademark, logo, or the like.

This is a continuation of application Ser. No. 07/473,897 filed on Feb.2, 1990, now U.S. Pat. No. 5,006,362which was a continuation of Ser. No.07/191,704 filed May 9, 1988, now abandoned.

TECHNICAL FIELD

This invention is in the field of applying indicia to pharmaceuticaldosage forms, food products and confectionery items using an ink thatprimarily has a water base.

BACKGROUND OF THE INVENTION

This invention is concerned with a method of marking forms such asconfectionery products, food, pharmaceutical tablets, and hard and softgelatin capsules with a water based ingestible ink.

Reference is made to James C. Brown U.S. Pat. No. 3,258,347 issued onJun. 28, 1966 for "Edible Pharmaceutical Ink"; Roy Y. Sanders, Jr. U.S.Pat. No. 2,948,626 issued on Aug. 9, 1960 for "Edible Pharmaceutical Inkand Process of Using Same"; Chester J. Piotrowski U.S. Pat. No.3,694,237 issued on Sep. 26, 1972 for "Edible Ink"; and Stuart C. Porteret al. U.S. Pat. No. 4,543,370 issued on Sep. 24, 1985 for "Dry EdibleFilm Coating Composition, Method and Coating Form". These patents areincorporated herein by reference.

Prior art ingestible inks suitable for marking forms such asconfectionery products, food, pharmaceutical tablets, and hard and softgelatin capsules have a shellac base in ethyl alcohol. One of theproblems in marking such forms and one of the more important parametersfor these inks is drying time. Brown U.S. Pat. No. 3,258,347, whichrefers to drying time as "set-to-touch-time", states that the optimumtransfer characteristics of the ink are obtained when theset-to-touch-time is two to four minutes. When the drying time is tooslow, as is discussed in Sanders, Jr. U.S. Pat. No. 2,948,626, atackiness problem develops resulting in spotting or smudging of the ink.Drying time is also discussed in Piotrowski U.S. Pat. No. 3,694,237 atcolumn 1, lines 57-72 which states: "Prior art edible inks are made withdry shellac, ethyl alcohol, plasticizers and/or detackifiers, pigments,or dyes, and solvents which give a desired drying time, say threeminutes. As the ink ages, a process occurs wherein the acid groups ofthe shellac react with the ethyl alcohol to form an ethyl ester of theshellac. The presence of the shellac ester increases the drying time ofthe ink, and as the amount or percentage of ester increases, the dryingtime is increased, eventually to a point where the drying time is toolong, causing offset, or pick-off, or transfer of the ink from oneprinted piece or tablet to another. Accordingly, it has been noted thatthe drying time of prior art inks increases with age, and this limitsthe shelf or storage life of the ink."

The machines presently being used to print marks onto pharmaceutical,food or confectionery products use a principle that is best described asoffset gravure. An engraved cylinder picks up ink as it rotates in anink bath. Excess ink is wiped off the engraved cylinder by a doctorblade and the ink remaining in the gravure etch of the cylinder istransferred to a rubber transfer (offset) roller which rotates with itsroller surface in contact with the engraved cylinder. The ink on thetransfer roller is then deposited onto the end product such as a tablet,or capsule.

The form may have been film coated, sugar coated, or not coated at all.To date, almost all inks used for this purpose have been of a shellacbase in ethyl alcohol. While some shellac based inks have incorporatedsome water into the formula by the modification of pH, the inks remainalcohol based for the most part. Accordingly, their closed cup flashpoint is less than 100° F., and, therefore, they must be labeled as ahazardous flammable liquid.

SUMMARY OF THE INVENTION

A pharmaceutically or confectionery acceptable ingestible ink for use onpharmaceutical, confectionery and food forms, such as hard and softshell gelatin capsules, tablets, candy and the like, comprises about 3to 15 parts polymer, 5 to 30 parts pigment, 0.0 to 20.0 partsplasticizer, 0.0 to 17.0 parts alcohol, 0.0 to 0.001 parts antifoamingagent, and sufficient water to make 100 parts, by weight of the ink. Apreferred ink formulation comprises about 10 parts polymer, 22 partspigment, 7 parts HPMC (6 cps), 12 parts alcohol, 0.001 partsanti-foaming agent, and sufficient water to make 100 parts, by weight,of the ink.

The polymer may be methylcellulose, hydroxypropyl methylcellulose(HPMC), hydroxypropyl cellulose (HPC), cellulose acetate phthalate,ethylcellulose, polyvinylpyrrolidone, sodium ethylcellulose sulphate,zein, polyvinylacetatephthalate, methacrylic acid-methacrylic acid esterco-polymer, or other film forming polymer used for coating tablets andthe like.

Any of the pigments heretofore used in making ingestible ink may be usedin the ink. Examples are discussed in Porter et al. U.S. Pat. No.4,543,370. Examples of pigments include FD&C and D&C lakes, titaniumdioxide, magnesium carbonate, talc, pyrogenic silica, iron oxides,channel black, and insoluble dyes. Also natural pigments such asriboflavin, carmine 40, curcumin, and annatto. Other examples are listedin Jeffries U.S. Pat. No. 3,149,040 and Butler et al. U.S. Pat. No.3,297,535, as well as in Signorino U.S. Pat. No. 3,981,984, which areincorporated herein by reference.

The plasticizer may be any of the polymer plasticizers discussed inPorter et al. U.S. Pat. No. 4,543,370. Exemplary of the polymerplasticizer are polyethyleneglycol, for example, polyethylene glycolhaving a molecular weight of 200 to 8000 (Carbowax by Union Carbide),glycerin, propylene glycol, Triacetin (Pfizer's glycerin triacetate),acetylated monoglyceride, and Citroflex 2 (triethyl citrate), Citroflex4 (tributyl citrate), Citroflex A2 (acetyl triethyl citrate), CitroflexA4 (acetyl tributyl citrate), diethyl phthalate, and mineral oil.Citroflex 2, 4, A2 and A4 are made by Pfizer and are plasticizersadapted for use with organic solvents.

The polymer plasticizer, to soften the polymer and make it less brittle,may be a liquid or a solid plasticizer, and a preferred plasticizer is aliquid such as polyethylene glycol 400.

Small amounts of alcohol may be used as a preservative or anti-foamagent. Examples of the alcohol that may be used are methanol, ethanol,isopropanol, and n-butanol, in amounts that are not sufficient to lowerthe flash point of the ink below 100° F. so as not to be classified asflammable by the Department of Transportation (DOT) of the U.S.government.

The antifoam may be Medical Anti-Foam (A-compound simethicone by DowCorning) or dimethyl polysiloxane.

The inks made from the above formula with the water soluble polymer andwith small amounts of alcohol still have a flash point above 100° F.,and therefore are not classified as a hazardous flammable liquid.

With all the water present in these inks there was concern about theability of the ink to dry on the offset gravure printing equipment usedin this process of marking tablets. Two properties of the formulaindicated possible problems. One is the latent heat of vaporation andthe other in the set-to-touch-time.

Looking at the following Table 1 of latent heats of vaporationillustrates the problem.

                  TABLE 1                                                         ______________________________________                                        MATERIAL    LATENT HEAT OF VAPORATION                                         ______________________________________                                        Water       540 Calories per gram                                             Ethanol     204 Calories per gram                                             Methanol    260 Calories per gram                                             Normal butanol                                                                            141 Calories per gram                                             ______________________________________                                    

Table 1 shows that to evaporate water requires from two to four timesthe amount of energy that is required to evaporate alcohol.

From Piotrowski U.S. Pat. No. 3,694,237, it is known that the idealset-to-touch-time for a shellac-alcohol ink is two to four minutes. Theset-to-touch-time for the inks disclosed in this patent application isfrom ten to 18 minutes.

Yet, in spite of all this evidence that teaches away from the presentinvention, the ink does perform very satisfactorily. The ink does nottransfer from the tablet because of slow drying.

This aqueous ink adheres to problem substrates from which shellacalcohol inks rub off after drying.

One process of making the ink is a wet process in which the inkcomponents are combined and run through dispersing mills in a liquidform.

Another process of making the ink is a dry process where the drycomponents are combined and run through a hammermill dry. The resultingdry material is combined with the liquid parts by mixing the drymaterial into the liquid in a blender. The resulting ink had the sameproperties as if it had been made by the wet process.

DETAILED DESCRIPTION

This invention is concerned with the composition of inks suitable foringestion that are used to mark forms such as confectionery products,food, pharmaceutical tablets, and hard and soft gelatin capsules,including medicinal tablets, vitamin tablets, aspirin tablets, capsules,chewing gum balls, cereal, cookies, meats, fruit, pasta, and the like.

The following examples illustrate the invention with the ingredientsbeing given in percent by weight and in grams.

EXAMPLE 1

    ______________________________________                                        Ingredients    Percent by Weight                                                                           Grams                                            ______________________________________                                        Water          49.00         2450                                             Propylene Glycol                                                                             10.00         500                                              Methanol       8.00          400                                              Isopropanol    4.00          200                                              HPMC (6 cps)   7.00          350                                              Black Iron Oxide                                                                             22.00         1100                                             ______________________________________                                    

(a) In a wet method, the propylene glycol, HPMC and black iron oxide aremixed into the water, and the resulting mixture is run through adispersing mill in liquid form for five minutes at room temperatureuntil a fine dispersion is obtained.

(b) In a dry method, the propylene glycol, HPMC and black iron oxide aremixed together and then run through a hammermill dry. The resulting drypower is then mixed into the water in a blender for about fifteenminutes at room temperature until a fine dispersion is obtained.

(c) The ink of Example 1(a) is placed into a bath of an offset gravureprinting machine where an engraved cylinder picks up the ink as itrotates in the bath, the excess ink is wiped off by a doctor blade, andthe remaining ink on the gravure etch of the engraved cylinder istransferred to a rubber transfer (offset) roller which transfers the inkonto tablets.

(d) The ink of Example 1(b) is poured into a bath of an offset gravureprinting machine when an engraved cylinder picks up the ink as itrotates in the bath, the excess ink is wiped off by a doctor blade, andthe remaining ink on the gravure etch of the engraved cylinder istransferred to a rubber transfer (offset) roller which contacts andtransfers the ink onto tablets.

Other examples of ink that illustrate the invention and that are made inaccordance with the wet method of Example 1(a) and are applied inaccordance with Example 1(c), or made as disclosed in Example 1(b) andapplied as in Example 1(d), are as follows.

EXAMPLE 2

    ______________________________________                                        Ingredients    Percent by Weight                                                                           Grams                                            ______________________________________                                        Water          49.00         2450                                             Propylene Glycol                                                                             10.00         500                                              Methanol       8.00          400                                              Isopropanol    4.00          200                                              HPMC (6 cps)   7.00          350                                              FD&C Blue      6.90          345                                              Aluminum Lake                                                                 Titanium Dioxide                                                                             15.10         755                                              ______________________________________                                    

EXAMPLE 3

    ______________________________________                                        Ingredients    Percent by Weight                                                                           Grams                                            ______________________________________                                        Water          49.00         2450                                             Propylene Glycol                                                                             10.00         500                                              Methanol       8.00          400                                              Isopropanol    4.00          200                                              HPMC (6 cps)   7.00          350                                              FD&C Red       19.30         969                                              Aluminum Lake                                                                 Titanium Dioxide                                                                             2.70          135                                              ______________________________________                                    

EXAMPLE 4

    ______________________________________                                        Ingredients    Percent by Weight                                                                           Grams                                            ______________________________________                                        Water          66.10         859.30                                           Methyl Alcohol 9.50          123.50                                           Black Iron Oxide                                                                             14.00         182.00                                           HPMC (15 cps)  5.70           74.10                                           Isopropyl Alcohol                                                                            4.70           61.10                                           ______________________________________                                    

EXAMPLE 5

    ______________________________________                                        Ingredient     Percent by Weight                                                                           Grams                                            ______________________________________                                        Water          66.00         924.00                                           Methyl alcohol 11.30         158.20                                           Propylene glycol                                                                             2.00          28.00                                            Black Iron Oxide                                                                             14.00         196.00                                           HPMC (15 Cps)  5.00          70.00                                            HPMC (3 cps)   0.70          9.80                                             HPC (LF)       1.00          14.00                                            ______________________________________                                    

EXAMPLE 6

    ______________________________________                                        Ingredients     Percent by Weight                                                                           Grams                                           ______________________________________                                        Water           55.00         770.00                                          Methyl Alcohol  14.00         196.00                                          Propylene Glycol                                                                              2.00          28.00                                           Normal Butyl Alcohol                                                                          3.00          42.00                                           Black Iron Oxide                                                                              14.00         196.00                                          HPMC (15 cps)   3.00          42.00                                           HPMC (5 cps)    3.00          42.00                                           HPMC (3 cps)    3.00          42.00                                           (HPC) Klucel LF 3.00          42.00                                           ______________________________________                                         Klucel LF is the LF grade of a hydroxypropyl cellulose made by Hercules,      Inc.                                                                     

EXAMPLE 7

    ______________________________________                                        Ingredients      Percent by Weight                                                                            Grams                                         ______________________________________                                        Water            80.29          1846.67                                       Black Iron Oxide 14.00          322.00                                        HPMC (15 cps)    5.70           131.10                                        Anti-foaming agent                                                                             0.01            0.23                                         (10% solution) Medicinal                                                      Antifoam (A-compound                                                          simethicone by Dow Chemical)                                                  ______________________________________                                    

EXAMPLE 8

    ______________________________________                                        Ingredients     Percent by Weight                                                                           Grams                                           ______________________________________                                        Water           61.16         795.08                                          HPMC (15 cps)   5.70           74.10                                          FD&C Red 40 Lake                                                                              17.50         227.50                                          Titanium Dioxide                                                                              2.50           32.50                                          Methanol        8.79          114.27                                          Isopropanol     4.35           56.55                                          ______________________________________                                    

EXAMPLE 9

    ______________________________________                                        Ingredient      Percent by Weight                                                                           Grams                                           ______________________________________                                        Water           61.16         856.24                                          HPMC (15 cps)   5.70           79.80                                          FD&C Blue 1 Lake                                                                              6.21           89.94                                          Titanium Dioxide                                                                              13.79         193.06                                          Methanol        8.79          123.06                                          Isopropanol     4.35           60.90                                          ______________________________________                                    

EXAMPLE 10

    ______________________________________                                        Ingredients   Percent by Weight                                                                           Grams                                             ______________________________________                                        Water         61.16         1,039.72                                          HPMC (15 cps) 5.70          96.90                                             Black Iron Oxide                                                                            20.00         340.00                                            Methanol      8.79          149.43                                            Isopropanol   4.35          73.95                                             ______________________________________                                    

EXAMPLE 11

    ______________________________________                                        Ingredients    Percent by Weight                                                                           Grams                                            ______________________________________                                        Water          66.20         926.80                                           Methanol       9.50          133.00                                           Isopropanol    4.70           65.80                                           HPMC (15 cps)  5.70           79.80                                           Titanium Dioxide                                                                             14.00         196.00                                           ______________________________________                                    

EXAMPLE 12

    ______________________________________                                        Ingredients     Percent by Weight                                                                            Grams                                          ______________________________________                                        SURELEASE (E-7-7050)                                                                          84.99          1,104.87                                       polymeric dispersion                                                          Black Iron Oxide                                                                              15.00            195.00                                       (Pigment)                                                                     Anti-foaming agent                                                                            0.01              0.13                                        (as in Example 7)                                                             ______________________________________                                    

The ink of example 12 is heat treated at 40° C. for one hour for thefilm to form completely. Also, any of the commercially availablesuspension polymer systems may be substituted for the SURELEASEdispersion, such as Aquacoat (from FMC corporation) and Eudragit (fromRohm Pharma GmbH, Darmstadt).

SURELEASE dispersion is a product of Colorcon, Inc., West Point, Pa.,and is a polymeric dispersion comprising ethylcellulose, dibutylsebacate, oleic acid, and fumed silica.

EXAMPLE 13

    ______________________________________                                        Ingredients     Percent by Weight                                                                           Grams                                           ______________________________________                                        Water           60.66         788.60                                          HPMC (6 cps)    5.70          74.00                                           Propylene glycol                                                                              0.50          6.48                                            FD&C Red No. 40 17.50         227.50                                          Aluminum Lake                                                                 Titanium Dioxide                                                                              2.50          32.50                                           Methanol        8.79          114.27                                          Isopropanol     4.35          56.55                                           ______________________________________                                    

The vehicle for the pigment is the polymer, which acts as a binder andcarrier for the pigment.

The preferred quantity of polymer, such as HPMC, used in producing theingestible inks of this invention is from about 3% to 15% by weight ofthe ink.

The percentage by weight of the inks of the polymer may vary due to theviscosity ranges of the polymer. For example, hydroxypropylmethylcellulose (HPMC) has common viscosity types of 3 cps, 6 cps, 15cps and 50 cps. The higher the viscosity, the more viscous (thicker) theink is. By weight of the ink, 7 percent by weight of the ink of 6 cpshydroxypropyl methylcellulose has been found to be advantageous.

Preferrably, the quantity of the pigment in the ink is approximately 5%to 30% by weight of the ink. Below 5%, printed ink is weak. Above 30%,the color of the printed ink is weak since a higher pigment-to-polymerratio affects the ability of the ink to transfer properly. Preferably,the pigment-to-polymer ratio when using 6 cps hydroxypropylmethycellulose is 7 parts of the 6 cps hydroxypropyl methylcellulose to22 parts of pigment. For different grades of hydroxypropylmethylcellulose, the pigment-to-polymer ratios differ.

The plasticizer softens the polymer and makes it less brittle. Theplasticizer also modifies the drying rate.

I have also found that my inks may be made without adding the customaryplasticizers, propylene glycol or polyethylene glycol; the water in thesystem may act as a plasticizer.

Alcohol may be used in my ink to modify the drying rate, to help reducefoaming, to help preserve the ink, and to increase the wetability of theink or reduce the surface tension. Above 17% by weight of the ink, thealcohol causes the ink to have a closed cup flash point below 100degrees Farenheit, thus requiring the ink to be labeled as a hazardousflamable liquid as defined by the Department of Transportation.Methanol, ethanol, isopropynol and n-butanol are the only alcoholsapproved for use by the Food and Drug Administration.

In addition to alcohol, other preservatives may be used, such as sodiumbenzoate.

The anti-foaming agent reduces foaming while the ink is on the printingmachine. The Food and Drug Administration limits the use of anti-foamingagents above 0.001% by weight of the finished ink. In addition toMedicinal Antifoam (A-compound simethicone by Dow Corning) and dimethylpolysiloxane, any acceptable food grade anti-foamer may be used in theink, if needed.

When making the ink, a wet process may be used, such as the method usedto make shellac type ink, disclosed in Brown U.S. Pat. No. 3,258,347.

Another process of making the ink is a dry process where the drycomponents are combined and run through a hammermill dry. The resultingdry material is combined with the liquid parts by mixing the drymaterial into the liquid in a blender. Previous shellac inks have notbeen made dry since the shellac could soften and prevent it from gettingthrough the hammermill.

ADVANTAGES

Performance of this aqueous ink is equal to and sometimes superior tothe performance of shellac based alcohol inks. Moreover, it is easier toclean this aqueous ink from the printing machine because, unlike shellacbased alcohol inks which require cleaning by alcohol solvents or byhighly caustic solutions, only water is needed to clean-up my inventivewater-based inks from the printing machines. Accordingly, operatorexposure to alcohol cleaning solvents and their fumes is greatlyreduced.

The inventive inks are not flammable at below 100° F. and are thereforeshipped more easily.

The wet and dry components of my ink may be kept separate from oneanother until ink is needed, and this extends the shelf life of the ink.Further, the settling out problem associated with prior art liquid inksuspensions is eliminated.

Inks made with the shellac alcohol system that uses aluminum lakes forpigments sometimes gel in a short period of time (less than a week).This is probably due to a reaction between the shellac and the aluminum.Inks produced in my water based system have not exhibited thisdisadvantage.

I claim:
 1. An ink composition for dispersal into water to form a waterbased ingestible ink for marking forms such as pharmaceutical tablets,capsules, confectioneries, or food using an offset gravure printingmachine, comprising a dry mixture of 3 to 15 parts polymer, 0 to 14parts plasticizer, and 5 to 30 parts pigment, said dry mixture to bedispersed with a sufficient amount of water to make 100 parts to formthe water based ingestible ink for marking forms using an offset gravureprinting machine, said dry mixture having a ratio of polymer to pigmenton a weight to weight basis, said ratio being about equal to or lessthan 1 part polymer for each part pigment.
 2. An ink composition fordispersal into water to form a water based ingestible ink for markingforms such as pharmaceutical tablets, capsules, confectioneries, or foodusing an offset gravure printing machine, comprising a dry mixture of 3to 15 parts polymer, 0 to 14 parts plasticizer, and 5 to 30 partspigment, said dry mixture to be dispersed with a sufficient amount ofwater to make 100 parts to form the water based ingestible ink formarking forms using an offset gravure printing machine, said dry mixturehaving an amount of polymer about equal to or less than the amount ofpigment in the dry mixture on a weight to weight basis.
 3. The inkcomposition of claim 2,the polymer being methylcellulose, hydroxypropylmethycellulose, hydroxypropyl cellulose, cellulose acetate phthalate,ethylcellulose, polyvinylpyrrolidone, sodium ethylcellulose sulphate,zein, polyvinylacetatephthalate, or methacrylic acid-methacrylic acidester co-polymer.
 4. The ink composition of claim 2,the plasticizerbeing polyethylene glycol having a molecular weight in the range of 200to 8000, glycerin, propylene glycol, glycerinetriacetate, acetylatedmonoglyceride, triethyl citrate, tributyl citrate, acetyl triethylcitrate, acetyl tributyl citrate, or diethyl phthalate.
 5. The inkcomposition of claim 2,the plasticizer being polyethylene glycol
 400. 6.The ink composition of claim 2,the plasticizer being a liquidplasticizer.
 7. The ink composition of claim 2,the pigment being FD&Cand D&C lakes, titanium dioxide, magnesium carbonate, talc, pyrogenicsilica, iron oxides, channel black, riboflavin, carmine 40, curcumin,annatto, or insoluble dyes.
 8. The ink composition of claim 2,theplasticizer being greater than 0 parts to 14 parts.
 9. A water-basedingestible ink for marking forms such as pharmaceutical tablets,capsules, confectioneries, or food using an offset gravure printingmachine, comprising3 to 15% by weight of a polymer, 0 to 14% by weightof a plasticizer, 5 to 30% by weight of a pigment, and water, said inkhaving a closed cup flash point equal to or above 100° F.
 10. Thewater-based ingestible ink of claim 9,the polymer being methylcellulose,hydroxypropyl methycellulose, hydroxypropyl cellulose, cellulose acetatephthalate, ethylcellulose, polyvinylpyrrolidone, sodium ethylcellulosesulphate, zein, polyvinylacetatephthalate, or methacrylicacidmethacrylic acid ester co-polymer.
 11. The water-based ingestibleink of claim 9,the plasticizer being polyethylene glycol having amolecular weight in the range of 200 to 8000, glycerin, propyleneglycol, glycerinetriacetate, acetylated monoglyceride, triethyl citrate,tributyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, ordiethyl phthalate.
 12. The water-based ingestible ink of claim 9,theplasticizer being polyethylene glycol
 400. 13. The water-basedingestible ink of claim 9,the plasticizer being a liquid plasticizer.14. The water-based ingestible ink of claim 9,the pigment being FD&C andD&C lakes, titanium dioxide, magnesium carbonate, talc, pyrogenicsilica, iron oxides, channel black, riboflavin, carmine 40, curcumin,annatto, or insoluble dyes.
 15. The water-based ingestible ink of claim9, further includingan alcohol in sufficient amount to act as apreservative and anti-foaming agent but insufficient in amount to lowerthe flash point below 100° F.
 16. The water-based ingestible ink ofclaim 15,the alcohol being methanol, ethanol, isopropanol, or n-butanol.17. The water-based ingestible ink of claim 15,the alcohol being about 0to 17% by weight of the ink.
 18. The water-based ingestible ink of claim9, further includingan anti-foaming agent.
 19. The water-basedingestible ink of claim 18,the anti-foaming agent being A-compoundsimathicone or dimethyl polysiloxane.
 20. The water-based ingestible inkof claim 18,the anti-foaming agent being A-compound simathicone fromabout 0 to 0.001% by weight of the ink.
 21. The ink of claim 9, said inkhaving a set-to-touch time ranging from 10 to 18 minutes.
 22. The ink ofclaim 9, the polymer, the plasticizer and the pigment being safelyingestible.
 23. The ink of claim 9, the ink consisting essentially ofthe polymer, the plasticizer, the pigment and water.
 24. The ink ofclaim 9, a range x of the plasticizer being 0<×≦14%.
 25. A water-basedingestible ink for marking forms such as pharmaceutical tablets,capsules, confectioneries, or food using an offset gravure printingmachine, comprising3 to 15% by weight of a polymer, 0 to 14% by weightof a plasticizer, 5 to 30% by weight of a pigment, and water, said inkhaving a closed cup flash point equal to or above 100° F., the polymerbeing methylcellulose, hydroxypropyl methycellulose, hydroxypropylcellulose, cellulose acetate phthalate, ethylcellulose,polyvinylpyrrolidone, sodium ethylcellulose sulphate, zein,polyvinylacetatephthalate, or methacrylic acid-methacrylic acid esterco-polymer, the plasticizer being polyethylene glycol having a molecularweight in the range of 200 to 8000, glycerin, propylene glycol,glycerinetriacetate, acetylated monoglyceride, triethyl citrate,tributyl citrate, acetyl triethyl citrate, acetyl tributyl citrate, ordiethyl phthalate, and the pigment being FD&C and D&C lakes, titaniumdioxide, magnesium carbonate, talc, pyrogenic silica, iron oxides,channel black, riboflavin, carmine 40, curcumin, annatto, or insolubledyes, and further includingan alcohol in sufficient amount to act as apreservative and anti-foaming agent but insufficient in amount to lowerthe flash point below 100° F., the alcohol being methanol, ethanol,isopropanol, or n-butanol, the alcohol being about 0 to 17% by weight ofthe ink, and an anti-foaming agent, the anti-foaming agent beingA-compound simathicone from about 0 to 0.001% by weight of the ink.